Chapter 16.2, Problem 22LC

Interpretation Introduction

Interpretation: The molarity of a solution is to be calculated.

Concept introduction: Molarity can be defined as the number of moles of solute present in the solution. Molarity is used to determine the concentration of the solution.

Answer to Problem 22LC

The molarity of the solution containing $400\text{ g CuSO4}$ in $4.00\text{ L}$ of solution is $\text{0}\text{.625 M}$

Explanation of Solution

To determine the concentration of the solution various terms are used such as molarity, molality, normality, percent by mass, and percent by volume. Molarity is the moles of solute present in the solution. The unit of molarity is $\frac{\text{mol}}{L}$

which is usually represented as M. The formula to calculate the molarity is defined as:

  $\text{Molarity = }\frac{n}{V}$

Where:

n is the number of moles of solute.

V is the volume of solution (in liters).

The data given in the question is as follows:

• Given the mass of copper sulfate (CuSO₄) is $400\text{ g}$ .
• Volume of the solution is $4.0\text{ L}$ .

The formula to determine the number of moles is as follows:

  $n=\frac{W}{M}$

Where:

W is the given mass of solute.

M is the molar mass of the solute.

Substitute the values in the above formula and calculate the number of moles of solute.

  $n=\frac{400\text{ g}}{159.609\frac{\text{g}}{\text{mol}}}$

  $n=2.5\text{ moles}$

Put the value of the number of moles and volume of solution to find the molarity of the solution.

  $\text{Molarity = }\frac{2.5\text{ moles}}{4.0\text{ L}}$

  $\text{Molarity = 0}\text{.625 M}$

Therefore, the molarity of the solution is $\text{0}\text{.625 M}$ .

Conclusion

The molarity of the solution containing $400\text{ g CuSO4}$ in $4.00\text{ L}$ of solution is $\text{0}\text{.625 M}$